Análise da atividade dos músculos respiratórios por meio da eletromiografia de superfície durante a mensuração do índice de esforço inspiratório cronometrado

Abstract

Introduction. Patients with acute respiratory failure often require invasive mechanical ventilation. Although lifesaving, it can induce respiratory muscle dysfunction. Respiratory muscle functional assessments might be useful in clinical practice. The timed inspiratory effort index (TIE), which assesses inspiratory muscle strength over time, was effective in predicting success in respiratory weaning. Surface electromyography (EMGs) can measure the behavior of the various respiratory muscle stores as well as their fatigability. Goal. To analyze the mechanical relationships between accessory and major muscle respiratory groups during the TIE index measurement procedure. Method. A prospective observational study with patients able to weaning from mechanical ventilation has done. The variables analyzed by the EMGs were the root mean square (RMS) for correlation with strength by the degree of recruitment of motor units over time, and the median frequency (FM) for assessment of fatigability potential. Data were obtained during the TIE index measurement procedure at three 20-second intervals. Were compared in patients with successful or fail during weaning from mechanical ventilation. P values <0.05 were considered significant. Results. Electromyography could identify differences on strength by RMS values in successful and failed weaning patients (P <0.05). Profile of fatigability could be compared in the groups using FM (P <0.05). Conclusion. The EMGs contributed to the understanding of the behavior of the respiratory muscles during the measurement of the TIE index, with the diaphragm being the most expressive muscle among the main group, while in the accessory muscle group, the sternocleidomastoid was more participative and its respective potentials. Fatigue were present in the group that failed respiratory weaning.